As a process of producing the hydroxyl group-containing 3-ethyloxetane compound, for example, a method of reacting 3-ethyl-3-chloromethyloxetane and 1,6-hexanediol in N,N-dimethylformamide in the presence of sodium hydride to produce 3-ethyl-3-(6-hydroxyhexyl)oxymethyloxetane at yield 61% is disclosed conventionally (cf., for example, Non-patent Document 1). However, this method had the problem that sodium hydride associated with the complicated handling must be used. Said document does not mention any of oxetane compounds other than 3-ethyl-3-(6-hydroxyhexyl)oxymethyloxetane.
Also, as a reaction between a 3-ethyloxetane compound and a diol compound, known is, for example, a method of reacting a sulfonate ester of 3-alkyl-3-hydroxymethyloxetane and a diol in the presence of the base. But a material produced from any of substrates by this method is a bisoxetane ether compound (cf., for example, Patent Document 3). It was not possibly conceivable that the 3-ethyloxetane compound containing a hydroxyl group of the present invention can be provided by a reaction between the 3-ethyloxetane compound and the diol.    Non-patent Document 1: Macromolecules, 38, 1640 (2005)    Patent Document 3: JP-A-2000-302774